Reliable engraftment, low toxicity, and durable remissions following allogeneic blood stem cell transplantation with minimal conditioning.

OBJECTIVE: Allogeneic blood stem cell transplantation (BSCT) can cure patients with hematologic malignancies by high-dose chemotherapy and allogeneic graft-vs-tumor (GvT) reactions. To avoid high-dose conditioning and evaluate engraftment, toxicity, and GvT reactions, we treated a group of high-risk patients with a minimal intensive conditioning regimen followed by allogeneic BSCT. MATERIALS AND METHODS: Thirty-four patients with lymphoma (11), myeloma (10), chronic myeloid leukemia (4), myelodysplastic syndrome (5), and acute myeloid leukemia (4) were treated with fludarabine (3 x 30 mg/m(2)) and 200 cGy total-body irradiation followed by the infusion of peripheral blood stem cells from related (28) or unrelated (6) donors. Cyclosporine or tacrolimus and mycophenolate mofetile were given posttransplant. Most patients had advanced disease, were intensively pretreated, and had contraindications against conventional myeloablative transplantation. RESULTS: Thirty-two patients (94%) had engraftment of donor cells. Patients with lymphatic malignancies developed complete donor chimerism significantly faster than patients with myeloid malignancies (p < 0.05). Clinical responses were observed in 16 of 27 patients (59%) who had active disease at transplantation. Of 7 patients who were treated in remission, 5 remain free of disease. After a median follow-up of 325 days (range 100-844) 22 patients are alive (65%, 14 CR, 4 PR, 4 PD). Two patients (6%) died of treatment-related complications and 10 patients (29%) died of progressive disease. Acute graft-vs-host-disease (GvHD) of grade II or more developed in 17 patients (50%). Chronic GvHD is present in 10 of 22 patients (45%) who are alive beyond day 100. CONCLUSIONS: Toxicity and survival in this group of high-risk patients are superior to those expected with conventional allogeneic transplantation. GvT reactions frequently occur in conjunction with GvHD and can induce durable remissions in patients with advanced hematologic malignancies.

Differential gene expression of bone marrow-derived CD34+ cells is associated with survival of patients suffering from myelodysplastic syndrome.

One feature of the molecular pathology of myelodysplastic syndromes (MDS) is aberrant gene expression. Such aberrations may be related to patient survival, and may indicate to novel diagnostic and therapeutic targets. Therefore, we aimed at identifying aberrant gene expression that is associated with MDS and patient survival. Bone marrow-derived CD34+ hematopoietic progenitor cells from six healthy persons and 16 patients with MDS were analyzed on cDNA macroarrays comprising 1,185 genes. Thereafter, our patients were followed-up for 54 months. We found differential expression of genes that were hitherto unrecognized in the context of MDS. Differential expression of 10 genes was confirmed by quantitative real-time RT-PCR. Hierarchical cluster analysis facilitated the separation of CD34+ cells of normal donors from patients with MDS. More importantly, it also distinguished MDS-patients with short and long survival. Scrutinizing our cDNA macroarray data for genes that are associated with short survival, we found, among others, increased expression of six different genes that encode the proteasome subunits. On the other hand, the most differentially down-regulated gene was IEX-1, which encodes an anti-apoptotic protein. We confirmed its decreased expression on RNA and protein level in an independent validation set of patient samples. The presented data broadens our notion about the molecular pathology of MDS and may lend itself to better identify patients with short survival. Furthermore, our findings may help to define new molecular targets for drug development and therapeutic approaches for patients with poor prognosis.

X-linked sideroblastic anemia associated with a novel ALAS2 mutation and unfortunate skewed X-chromosome inactivation patterns.

Historically X-linked sideroblastic anemia, with rare exceptions, was thought to be manifested only in males. Since the discovery of the erythroid-specific isoform of 5-aminolevulinate synthase (ALAS2) and the cloning of its gene (ALAS2) 15 years ago, mutation analysis has revealed that clinical expression of this X-linked disorder is prevalent in females as well. However, presence of the disease in both genders within affected kindreds appears to be very uncommon. We report a unique family with the disorder in three women who have had widely disparate clinical courses. The anemia is associated with a previously unrecognized ALAS2 mutation (Arg436Trp) and is unresponsive to pyridoxine. To clarify the varied clinical courses of the patients, X-chromosome inactivation patterns were examined in hematopoietic and non-hematopoietic cells. We observed inactivation patterns supporting the conclusions that one daughter has a mild phenotype at age 31 because of moderate constitutive skewed X-chromosome inactivation, another daughter with clinical onset at age 16 is severely affected due to extreme constitutive X-skewing, whereas the mother developed progressive anemia in the fifth decade as she acquired an age-related non-random X-inactivation in hematopoietic cells. In addition, we observed random X-inactivation in reticulocytes of all three women that contrasted with a markedly skewed inactivation pattern in bone marrow erythroid cells. This discordance is attributable to apoptosis of erythroid precursors derived from progenitor cells with an active X-chromosome bearing the ALAS2 mutation. The features of the disorder in this family are also instructive in regard to the differential diagnosis of sideroblastic anemias in women.

Quantitative real-time reverse-transcription polymerase chain reaction for diagnosis of BCR-ABL positive leukemias and molecular monitoring following allogeneic stem cell transplantation.

Real-time reverse-transcription polymerase chain reaction (RT-PCR) (qPCR) of the BCR-ABL mRNA is a suitable technique to measure the amount of circulating leukemic cells in chronic myelogenous leukemia (CML). In this study, we evaluated a BCR-ABL-specific qPCR method using the LightCycler technology in 95 patients with Philadelphia chromosome positive acute leukemia (n = 7) or CML in different stages (n = 88). Primers and hybridization probes were chosen to detect the most prevalent variants of BCR-ABL (b2a2, b3a2, b2a3, b3a3, e19a2, e1a2) with a sensitivity of 10-5 for b2a2 and b3a2. With median BCR-ABL/G6PDH ratios of 10.7% in the untreated chronic phase, 43.2% in the newly diagnosed accelerated phase, and 131.4% in newly diagnosed blast crisis the BCR-ABL mRNA levels varied significantly between different stages of CML whereas no difference was found between blast crisis and untreated acute leukemias (136.9%). There was a strong relationship between qPCR results and cytogenetics in patients treated with imatinib, interferon-alpha, or following allografting. Thirteen patients with CML were sequentially examined by qPCR following myeloablative or non-myeloablative allogeneic peripheral blood stem cell transplantation. Five patients received donor lymphocytes and became BCR-ABL negative as confirmed by nested RT-PCR. The gradual disappearance of BCR-ABL positive cells could be monitored by qPCR following non-myeloablative transplantation. Comparison of BCR-ABL levels with the degree of donor chimerism showed that 91% of samples with complete donor chimerism were BCR-ABL negative. In 22% of BCR-ABL negative samples chimerism between 71% and 98% was observed, indicating the persistence of normal recipient's hematopoietic cells. In conclusion, the qPCR protocol used in this study is a reliable and fast method for monitoring molecular response in CML.